\Ar`go*nau"ta\, n. (Zo["o]l.)
A genus of Cephalopoda. The shell is called paper nautilus or
paper sailor.
Note: The animal has much resemblance to an Octopus. It has
      eight arms, two of which are expanded at the end and
      clasp the shell, but are never elevated in the air for
      sails as was formerly supposed. The creature swims
      beneath the surface by means of a jet of water, like
      other cephalopods. The male has no shell, and is much
      smaller than the female. See {Hectocotylus}.